i am having trouble with the divide function in the main. any help would be great.

Code:

#include <iostream>
#include "fun.h"
using namespace std;
double divide (double num1, double num2);
int main()
{
double a, b, c; //declares variables
cout<<"Enter two numbers:"; //displays output
cin>>a>>b; //gets input
cout<<endl; //ends line
/**************************************
* Adds the value of a and b *
* @param a a double *
* @param b a double *
* @return the sum of the two inputs*
**************************************/
c=add(a,b);
cout<<"The sum of the two numbers is: " <<c;
cout<<endl;
/***************************************
* Subtracts the value of a and b *
* @param a a double *
* @param b a double *
* @return the diff of the two inputs*
***************************************/
c=subtract(a,b);
cout<<"The difference of the two numbers is: " <<c;
cout<<endl;
/******************************************
* Mutiplies the value of a and b *
* @param a a double *
* @param b a double *
* @return the product of the two inputs*
******************************************/
c=multiply(a,b);
cout<<"The product of the two numbers is: " <<c;
cout<<endl;
/***************************************
* Cubes the value of a and b *
* @param a a double *
* @param b a double *
* @return the cube of one input *
***************************************/
c=cube(a);
cout<<"The cube of the first number is: " <<c;
cout<<endl;
/***************************************
* Cubes the value of a and b *
* @param a a double *
* @param b a double *
* @return the cube of one input *
***************************************/
c=cube(b);
cout<<"The cube of the second number is: " <<c;
cout<<endl;
double divide (double num1, double num2)
{
double total;
total = num1 / num2;
return total;
}
return 0;
}